Characterization of three co-circulating genotypes of the small hydrophobic protein gene of mumps virus

Eighteen virus isolates and 22 serum samples collected between 1971 and 199 7 from patients with mumps were genotyped by PCR with specific primer pairs for the A, C and D genotypes of the small hydrophobic (SH) protein gene. A ll serum samples were subjected to nucleotide sequence analysis of the gene , and the deduced 57-amino-acid sequences were aligned with previously publ ished sequences from the USA, Canada, Portugal, the UK, France, Germany, Sw itzerland, Denmark, Sweden, Russia, China and Japan. The existence of six g enotypes of the SH protein gene, named A to F, was confirmed. In the Stockh olm area, co-circulation of genotypes A, C and D at different times was fou nd. There was a striking difference in genotype between the virus isolates and the serum samples. The 18 virus isolates represented genotypes C and D, whereas the 22 serum samples contained genotype A. In most cases, the amin o acid sequences of the 22 genotype A specimens were identical to the previ ously described SBL-1 strain of genotype A. Genotypes C and D were always a ssociated with meningitis, and in some cases parotitis, whereas infection w ith genotype A most often resulted in parotitis and seldom in meningitis.